Serum undercarboxylated osteocalcin levels are inversely associated with glycemic status and insulin resistance in an elderly Japanese male population: Fujiwara-kyo Osteoporosis Risk in Men (FORMEN) Study

SUMMARY

Recent animal studies have demonstrated that undercarboxylated osteocalcin upregulates insulin secretion via osteoblast-insulin signaling. However, it remains unclear whether such a pathway exists in humans. This study showed that serum undercarboxylated osteocalcin levels were inversely associated with fasting plasma glucose, hemoglobin A(1c), and homeostasis model assessment of insulin resistance (HOMA-IR) levels in community-dwelling elderly Japanese men.

INTRODUCTION

Undercarboxylated osteocalcin (ucOC) was reported to increase insulin secretion and improve glucose tolerance via osteoblast-insulin signaling in animal-based studies. Whether this pathway also exists in humans is unknown. We aimed to clarify whether serum ucOC levels are associated with glycemic status and insulin resistance in the general Japanese population.

METHODS

We included 2,174 Japanese men (≥65 years) who were able to walk without aid from others and lived at home in four cities of Nara Prefecture. We excluded participants with a history of diseases or medications that affect bone metabolism, other than type 2 diabetes mellitus (T2DM). Fasting plasma glucose, glycated hemoglobin A(1c), and HOMA-IR levels were determined as outcome measures.

RESULTS

Of the 1,597 participants included in the analysis, both intact OC (iOC) and ucOC levels showed significant inverse correlations with all outcome measures, even after adjusting for potential confounders. Mean values of outcome measures showed a significant decreasing trend with higher quintiles of iOC or ucOC after adjusting for confounders. This trend remained significant for ucOC quintiles after further adjustment for iOC levels, but was not significant for iOC quintiles after adjusting for ucOC levels. These results were attenuated, but still apparent, after excluding participants receiving drug therapy for T2DM.

CONCLUSIONS

Levels of ucOC, but not iOC, were inversely associated with glycemic index and insulin resistance in a population of Japanese men. These findings will need to be confirmed with longitudinal studies.

Trends of allergic symptoms in school children: large-scale long-term consecutive cross-sectional studies in Osaka Prefecture, Japan

BACKGROUND

Trends in the prevalence rates of allergic symptoms in children have been discussed extensively, but it remains uncertain which symptoms increase or decrease over time owing to the lack of large-scale long-term consecutive cross-sectional studies performed on a representative population of children.

OBJECTIVE

To clarify the trends in the prevalence rates of allergic symptoms in Japanese children.

METHODS

Total population questionnaire surveys were conducted 15 times from 1975 to 2006 for all children attending public elementary schools in Osaka Prefecture, Japan, with the number of subjects ranging from 460,000 to 900,000. Parents of the children completed the questionnaire about allergic symptoms and other symptoms, including wheeze, physician-diagnosed atopic dermatitis, rhinitis, and itching eyes.

RESULTS

Response rates were consistently over 90%. The prevalence of wheezing was constant until 1983, then increased from 1983 until 1993, then stabilized at about 4.4%. The lifetime prevalence of atopic dermatitis increased to 24% by 1993, and then decreased. The prevalence of rhinitis increased to 25% by 2003, whereas the prevalence of non-seasonal symptoms plateaued from 1993 on at 11% and vernal symptoms increased. The prevalence of itching eyes continued to increase to 21% in 2006, and vernal symptoms increased sharply.

CONCLUSIONS

In Osaka Prefecture, Japan, the turning point when the prevalence of wheezing in schoolchildren had begun to increase was 1983. And the turning point when the increase in the prevalence of wheezing, atopic dermatitis, and non-seasonal allergic rhinitis turned to decrease or constant was 1993. The prevalence of rhinitis and itching eyes in spring was still increasing in 2006.

Autopsy cases of lung cancer and liver cancer among Japanese dentists--a review of the annual of the pathological autopsy cases in Japan

Dentists are exposed to carcinogenic metals during their work. It has been speculated that dentists are also at high risk for occupational exposure to bloodborne viruses such as hepatitis B and hepatitis C. We suspected that Japanese dentists were at increased risk for lung and liver cancer. To assess this question, we compared the number of pathological diagnoses of lung cancer and liver cancer among autopsy cases of male dentists (n=225) with that among autopsy cases of male medical doctors (n=1,296), based on data from the Annual of the Pathological Autopsy Cases in Japan from 1992 to 1999. We calculated the mortality odds ratio of lung cancer and liver cancer, using stomach cancer as the control. No difference between the dentist group and the medical doctor group was observed in the pathological diagnoses of lung cancer among all autopsy cases (p=0.703, Odds Ratio: 0.846, 95% confidence interval: 0.461-1.554). Liver cancer was observed less often among dentists than among medical doctors (p=0.047, Odds Ratio: 0.474, 95% confidence interval: 0.239-0.941). Based on the results of this study, we suggest that Japanese male dentists do not have a higher risk of developing lung cancer than male medical doctors, and have a lower risk of developing liver cancer.

Alcohol intake and bone status in elderly Japanese men: baseline data from the Fujiwara-kyo osteoporosis risk in men (FORMEN) study

There are no data concerning a relationship between alcohol and bone status from a large-scale community-based study of elderly Japanese men. The baseline survey for the Fujiwara-kyo Osteoporosis Risk in Men Study was performed in 2174 male participants during the period from 2007 to 2008 in Nara Prefecture, Japan. Among them 1665 fitted the following inclusion criteria: (a) age ≥65years, (b) no diseases or drug therapy that could affect bone mineral density (BMD). We analyzed 1421 men with complete information about alcohol intake. We found that alcohol intake and BMD were positively correlated after adjustment for age, body mass index, natto intake, milk intake, smoking, physical activity, education, marital status, and hypertension. Adjusted total hip BMD of men with alcohol intake >39g/day was 0.90g/cm(2) and that of abstainers was 0.85g/cm(2). With regard to bone turnover markers, alcohol intake was inversely associated with serum levels of osteocalcin and tartrate-resistant acid phosphatase isoenzyme 5b. A two-piece linear regression model revealed a positive relationship between alcohol intake and crude mean BMD for the total hip in those with alcohol intake of less than 55g/day. In contrast, alcohol intake and BMD in those with an alcohol intake of 55g/day or more was inversely correlated. The present large-scale study of elderly Japanese men revealed that although an alcohol intake of <55g/day was positively correlated to BMD, alcohol intake of ≥55g/day was inversely correlated to BMD.

Effect of recovery from obesity on cardiovascular risk factors among Japanese schoolchildren: the Iwata population-based follow-up study

BACKGROUND

The effect of recovery from obesity on cardiovascular risk factors is not well understood in Japanese children.

METHODS

We analyzed follow-up data from the Iwata city population-based study of schoolchildren in Japan. The Iwata Board of Education conducted health screenings of children aged 10 and 14 years. A total of 914 children aged 10 years (451 boys and 463 girls, 87.1% of all children in the city in 1997) were followed until 14 years of age and classified by pattern of obesity as Normal, Recovered, Worsened, or Persistent.

RESULTS

Of the 914 children, 111 (12%) were obese at 10 years of age. Of those children, 44 (40%) were no longer obese at 14 years (ie, Recovered). At follow-up, Recovered boys had the greatest decrease in non-HDL cholesterol (mean ± SE, -21.3 ± 3.6 mg/dL) among the 4 groups, and Recovered girls had a significantly lower level of non-HDL cholesterol (Recovered, 107.1 ± 5.4 mg/dL vs. Persistent, 126.1 ± 4.5 mg/dL). The Recovered boys also had a significantly higher level of HDL cholesterol at age 14 (Recovered, 67.2 ± 2.7 mg/dL vs. Persistent, 53.3 ± 2.1 mg/dL). In the Recovered group, 68% of children who were dyslipidemic at baseline had normal cholesterol levels at age 14. The recovery rate from dyslipidemia was significantly higher in the Recovered group (cumulative incidence rate ratio, 2.5; 95% confidence interval, 1.4-4.7) as compared with the Persistent group.

CONCLUSIONS

Dyslipidemia was reversed in children who recovered from obesity. Our findings suggest that reducing obesity is beneficial to the health of Japanese schoolchildren.

Cut-off values of body mass index, waist circumference, and waist-to-height ratio to identify excess abdominal fat: population-based screening of Japanese school children

Background

School-based screening and prevention programs for adiposity generally target school children in grades 4 and 6 (age 9–11 years). The aims of this study were to evaluate the validity of body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR) in identifying abdominal adiposity in fifth-grade Japanese school children and to determine optimal cut-off values for anthropometric measures.

Methods

The target population was fifth-grade school children enrolled in 2 schools in Shizuoka, Japan between 2008 and 2010; 422 of the 466 children participated in the present study. Abdominal adiposity was defined as percent trunk fat in the 95th percentile or higher, as determined by dual-energy x-ray absorptiometry (DXA). We analyzed the validity of BMI, WC, and WHtR using receiver operating characteristic (ROC) curve analysis. The Youden index was used to determine cut-off values of BMI, WC, and WHtR that identify excess abdominal fat.

Results

Optimal cut-off values to identify abdominal adiposity were 20.8 kg/m² (BMI), 76.5 cm (WC), and 0.519 (WHtR) for boys, and 19.6 kg/m² (BMI), 73.0 cm (WC), and 0.499 (WHtR) for girls. Areas under the ROC curve were 0.983 (BMI), 0.987 (WC), and 0.981 (WHtR) for boys, and 0.981 (BMI), 0986 (WC), and 0.992 (WHtR) for girls.

Conclusions

BMI, WC, and WHtR successfully identified a high proportion of children with excess abdominal fat as measured by DXA, demonstrating that these measures are useful indices for school screening.

Height-specific serum cholesterol levels in pubertal children: data from population-based Japanese school screening

Background

Inverse associations between height and serum lipid levels in pubertal children have been reported. To develop criteria for normal serum lipid levels stratified by height in pubertal children, we examined height-specific cholesterol levels, using data from a population-based school screening.

Methods

Serum levels of total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C) were investigated in 10 151 children (98.9% of the target population) aged 10 and 14 years who attended public schools in Iwata City from 2002 through 2007.

Results

The 95th percentiles of TC in the lowest and highest quintiles of height were 221 and 219 mg/dL, respectively, in 10-year-old boys, 215 and 203 mg/dL in 14-year-old boys, 220 and 204 mg/dL in 10-year-old girls, and 226 and 214 mg/dL in 14-year-old girls. The fifth percentiles of HDL-C in the lowest and highest quintiles of height were 45 and 43 mg/dL in 10-year-old boys, 43 and 40 mg/dL in 14-year-old boys, 46 and 42 mg/dL in 10-year-old girls, and 47 and 44 mg/dL in 14-year-old girls.

Conclusions

This study provided height-specific levels of serum lipids in 10-year-old and 14-year-old children. Height should be considered when evaluating cholesterol levels in pubertal children.

Impact of smoking on bone mineral density and bone metabolism in elderly men: the Fujiwara-kyo Osteoporosis Risk in Men (FORMEN) study

Our cross-sectional analysis of 1,576 men aged ≥65 years examined smoking effects on bone status. Number of smoking years was associated with decreased bone mineral density (BMD), after adjusting for age, height, weight, and number of cigarettes smoked daily. Smoking did not affect biochemical marker serum values for bone turnover.

INTRODUCTION

The impact of smoking on bone status in men has not been conclusively established. We examined how smoking and its cessation influence bone status and metabolism in men.

METHODS

We analyzed 1,576 men among a baseline survey of Japanese men aged ≥65 years, the Fujiwara-kyo Osteoporosis Risk in Men study, conducted during 2007-2008.

RESULTS

Lumbar spine (LS) BMD values among never, former, and current smokers were 1.045 ± 0.194, 1.030 ± 0.189, and 1.001 ± 0.182 g/cm(2) (P = 0.005), respectively, while total hip (TH) BMD values were 0.888 ± 0.120, 0.885 ± 0.127, and 0.870 ± 0.124 (P = 0.078), respectively. The significant trend for LS BMD remained after adjusting for the covariates; age, height, weight, physical activity, milk consumption, and drinking habit (P = 0.036). Among never and ever (current and former) smokers, LS and TH BMD decreased with the number of pack years or the number of smoking years, respectively, adjusted for those covariates. Among ever smokers, LS and TH BMD decreased with the number of smoking years after adjusting for age, height, weight, and number of cigarettes smoked daily. Smoking did not reveal significant effect for serum osteocalcin or tartrate resistant acid phosphatase isoenzyme 5b.

CONCLUSION

The impact of smoking on bone status is mainly associated with the number of smoking years in elderly men.

Beneficial effects of mild stress (hormetic effects): dietary restriction and health

Hormesis is defined as a dose-response phenomenon characterized by low-dose stimulation and high-dose inhibition, and has been recognized as representing an overcompensation for mild environmental stress. The beneficial effects of mild stress on aging and longevity have been studied for many years. In experimental animals, mild dietary stress (dietary restriction, DR) without malnutrition delays most age-related physiological changes, and extends maximum and average lifespan. Animal studies have also demonstrated that DR can prevent or lessen the severity of cancer, stroke, coronary heart disease, autoimmune disease, allergy, Parkinson's disease and Alzheimer's disease. The effects of DR are considered to result from hormetic mechanisms. These effects were reported by means of various DR regimens, such as caloric restriction, total-nutrient restriction, alternate-day fasting, and short-term fasting. Mild dietary stress, including restriction of amount or frequency of intake, is the essence of DR. For more than 99% of their history, humans lived as hunter-gatherers and adapted to restrictions in their food supply. On the other hand, an oversufficiency of food for many today has resulted in the current global epidemic of obesity and obesity-related diseases. DR may be used, therefore, as a novel approach for therapeutic intervention in several diseases, when detailed information about effects of mild dietary stress on human health is obtained from clinical trials.

Relationship between height and blood pressure in Japanese schoolchildren

BACKGROUND

Blood pressure examinations for health education use have been conducted at several schools in Japan. It has been reported that blood pressure is closely associated with bodyweight and height in US children. The aim of the present paper was to evaluate the association between height and blood pressure in Japanese schoolchildren.

METHODS

In Iwata city in Japan, blood pressure screening was conducted by the school administration. A total of 98.9% (10,152/10,270 children) of all fifth (10-year-olds) and ninth graders (14-year-olds) residing in the Old Iwata area from 2002 to 2007 were analyzed.

RESULTS

In 10-year-old and 14-year-old boys, regression analysis indicated that a positive correlation between weight and blood pressure was the strongest among the three body size indices (height, weight, and body mass index), but the association between height and blood pressure was also significant. For girls from both the 10 and 14 year age groups, the correlation of weight and blood pressure was stronger than those for the other body size indices, but there were also significant associations between height and blood pressure, except for height and diastolic blood pressure in the 14-year-olds.

CONCLUSIONS

There is a significant positive relationship between height and blood pressure. Further study is necessary to provide a blood pressure reference based on height in the Japanese program to prevent children from developing lifestyle-related risk factors.

Trends in body mass index, blood pressure, and serum lipids in Japanese children: Iwata population-based annual screening (1993-2008)

Background

Current trends in body size, blood pressure, and serum lipids in children are predictors of future disease prevalence. However, there have been no studies of blood pressure and high-density lipoprotein cholesterol (HDL-C) levels in Japanese children.

Methods

We investigated trends in body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol (TC), non-HDL-C, and HDL-C using data from annual screenings in 1993 through 2008. The subjects were 14 872 (98.8% of the target population) fifth-graders enrolled in all public schools in the Original Iwata area in Iwata City, Japan. The same examination protocol was used throughout to ensure the uniformity of quality control and the precision of assessment. Trends in the variables in relation to the calendar year were analyzed by using regression models.

Results

In boys, the 95th percentile of BMI increased by 0.09 kg/m²/year. In both sexes, the 5th percentile of BMI decreased by 0.02 to 0.03 kg/m²/year. There was a significant negative correlation between SBP and calendar year, and the 95th percentile of SBP decreased by 0.52 mm Hg/year in boys and by 0.40 mm Hg/year in girls. There was also a significant reduction DBP. However, there were no trends in TC, non-HDL-C, or HDL-C.

Conclusions

The increase in obese and underweight children in Original Iwata was consistent with the findings of a nationwide survey. Although high blood pressure and related risk factors were formerly a serious problem in Japan, blood pressure levels have decreased in schoolchildren from Iwata over the past 15 years.

Design and baseline characteristics of a prospective cohort study for determinants of osteoporotic fracture in community-dwelling elderly Japanese men: the Fujiwara-kyo osteoporosis risk in men (FORMEN) study

BACKGROUND

Osteoporosis and osteoporotic fracture in men are significant public health problems in an aging society. However, information on male osteoporosis remains impressively lacking, especially for Asians. We designed the Fujiwara-kyo Osteoporosis Risk in Men (FORMEN) study as an ancillary study of a cohort study, the Fujiwara-kyo study, to determine risk factors for osteoporotic fractures in Japanese men.

METHODS/DESIGN

DESIGN

A community-based single-centre prospective cohort study with at least a 5-year follow-up.

SUBJECTS

All the male participants of the Fujiwara-kyo study who were living in the four cities studied, aged 65 years and older, and able to walk without aid from others.

PRIMARY OUTCOME

Incidence of osteoporotic fractures including vertebral and clinical non-vertebral fractures. ADDITIONAL OUTCOMES: Change in bone mineral density (BMD), change in hip geometry, onset of receiving benefits from Long-term Care Insurance (LCI), health-related quality of life, and mortality. BASELINE MEASUREMENTS: BMD at the lumbar spine (LS) and hip (TH), hip geometry, vertebral deformity assessment, bone turnover markers, physical and cognitive performance, various medical and lifestyle factors, and geriatric psychosocial measures confirmed by interviews based on self-administrated questionnaires.OUTCOME SURVEILLANCE: Annual mail surveys and a follow-up survey at the fifth year comprising similar items to the baseline study will be used to determine the outcomes. Receipt of benefits from LCI and mortality will be obtained from the city governments.

CURRENT STATUS

The baseline study was conducted for 2174 eligible men, and 2012 completed the study and were eligible for follow-up. Prevalence rates of osteoporosis (BMD 2.5 SD or more below the young adult mean (YAM)) and low BMD (BMD 1 SD or more below YAM) in at least one of LS and TH were calculated to be 4.4% and 41.8%, respectively. The proportion of men with low BMD only at TH showed a significant increasing trend with aging (p < 0.0001) while that only at LS showed a decreasing trend (p = 0.0386). The prevalence rate of osteoporosis was underestimated when diagnosed using only BMD at LS. Other baseline measurements were successfully obtained.

DISCUSSION

FORMEN baseline study was performed as designed and the FORMEN cohort study was successfully launched.

Smoking prevalence among dentists in Hyogo, Japan 2003

We examined smoking prevalence among dentists in Hyogo, Japan, as smoking would influence their smoking cessation interventions to encourage their patients to stop smoking. In 2003, a self-administered questionnaire was mailed to all members of the Hyogo Dental Association (HDA) in Japan. Of the 1,133 members of the HDA, 327 were current smokers (28.9%). Smoking prevalence among HDA members was significantly higher than that among Japan Medical Association (JMA) members in 2004, as previously reported (16.2%) (p<0.01). Although smoking prevalence among HDA members decreased overall in 2003 in comparison with 2000, smoking prevalence among dentists aged 20-39 yr increased. These findings indicate that smoking was more prevalent among dentists in Hyogo Prefecture than among Japanese medical doctors. It is important to promote smoking cessation among Japanese dentists so that dentists will be more likely to encourage their patients to quit smoking.

Taste development from health education among schoolchildren: a two-year intervention study

It is necessary to develop a system of nutritional education which can be understood among schoolchildren who have not yet received a basic education. In the present study, we conducted an educational program for lower-grade schoolchildren, which contained dish selection, an agricultural experience, a cooking experience, and a lecture on digestive absorption. We evaluated the effect of this program on development by measuring taste sensitivity regarding sweet, sour, salty and bitter tastes. For the baseline period, there was no significant difference between the intervention school and the control school in each variable. At follow-up periods, both the intervention and the control schools showed an increasing sense of taste. In the intervention school, development of sensitivity to the sweet, the sour, and the bitter taste was significant. In the control school, development of sensitivity to the sweet and the bitter taste was significant. The increases in the sense of the sour and the bitter tastes and the sum of the four tastes for the intervention subjects were significantly larger than comparable values for the control subjects. These results suggest that the development of taste sensitivity is affected by nutritional education for lower-grade elementary schoolchildren.

Metabolic response to short-term 4-day energy restriction in a controlled study

OBJECTIVES

Metabolic rate is affected not solely by diet but also by environmental characteristics such as climate and seasonal changes in day length. In the present study, we conducted a controlled study in which we observed metabolic response to short-term energy restriction (ER).

MATERIALS AND METHODS

Thirty-two subjects were divided randomly into a slight ER group and a moderate ER group. The energy intake per day for slight ER vs moderate ER was 1462 kcal vs 1114 kcal. During the 4-day study periods, the same daily timetable, which consists of nutrition, exercise, sleeping and others, was imposed on both groups. The same environment was also provided to both groups.

RESULTS

After the 4-day ER, significant decreases in body weight and basal metabolic rate (BMR) were shown in both groups. The decrease in body weight was 2% of the baseline level in both groups, and the decreases in the BMR were 6% of baseline levels in the slight ER group and 13% in the moderate ER group. The decrease in BMR in the moderate ER group was significantly larger than that in the slight ER group.

CONCLUSIONS

In a controlled study of short-term ER, we observed a significant decrease in BMR. There was a positive association between the degree of ER and the reduction in BMR. Reductions in BMR were greater than those in body weight. It, thus, appears that the minimization of weight loss is due to dramatic decreases in BMR. This suggests the existence of metabolic resistance against ER.

Interrelationships among whole-body coordination, functional potentiality, and environmental adaptability

The term "adaptability" or "capacity of adaptation" is the central concept in the general advancement and promotion of research in physiological anthropology. Throughout the history of Homo sapiens, mankind has adapted itself to environmental stress. As a result, numerous physiological polymorphisms in humans are present in our planet-wide distribution. Totally regulated physiological function by integration and coordination is referred to as whole-body coordination and is associated with a high degree of adaptability in humans. Functional potentiality also affects environmental adaptability. Thus, whole-body coordination and functional potentiality are necessary for adaptation to environmental changes. There is an interrelationship among functional potentiality, whole-body coordination, physiological polymorphisms, and environmental adaptability.